Clip the damage area horizontally if only a single scanline has been changed. This is helpful to reduce the memcpy overhead for small writes.
Signed-off-by: Thomas Zimmermann tzimmermann@suse.de Reviewed-by: Javier Martinez Canillas javierm@redhat.com --- drivers/gpu/drm/drm_fb_helper.c | 12 ++++++++++++ 1 file changed, 12 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 4d5410dd96c5..e05a7bd6fb12 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -690,6 +690,18 @@ static void drm_fb_helper_memory_range_to_clip(struct fb_info *info, off_t off, u32 x2 = info->var.xres; u32 y2 = DIV_ROUND_UP(end, info->fix.line_length);
+ if ((y2 - y1) == 1) { + /* + * We've only written to a single scanline. Try to reduce + * the number of horizontal pixels that need an update. + */ + off_t bit_off = (off % info->fix.line_length) * 8; + off_t bit_end = (end % info->fix.line_length) * 8; + + x1 = bit_off / info->var.bits_per_pixel; + x2 = DIV_ROUND_UP(bit_end, info->var.bits_per_pixel); + } + drm_rect_init(clip, x1, y1, x2 - x1, y2 - y1); }